1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to an image detection, and more particularly, to an apparatus and method for detecting an image converted from a first resolution to a second resolution higher than the first resolution in a digital video device.
2. Description of the Related Art
The development of compression technology for audio and video signals has aided the rapid transition of broadcasting systems from analog to a digital. Digital broadcasting video signals can be categorized as Standard Definition (SD) image signals and High Definition (HD) image signals according to their resolution, and each country adopts the SD and/or HD image signal according to its digital broadcast policy. High image quality can be achieved when the HD image signal is used as compared to the SD image signal. As the adoption of digital broadcasting increases, HD images converted from various sources are broadcasted. Images captured by various broadcasting devices, such as HD cameras, SD cameras, and HD camcorders, are converted to HD image and transmitted. There are two types of HD image signals transmitted by broadcasting stations: real HD image signals and HD image signals converted from image source captured using an SD method.
The generation of HD image from SD image is achieved using a scaling or up-converting method using an interpolation filter. For example, from 480i or 480p-SD image, 1080i, 1080p, or 720p-HD image is generated. If SD image is interleaved image, the interleaved image is scaled after progressive conversion is performed, or after a top field and a bottom field are separately scaled without the progressive conversion, interleaved image is generated. In this case, HD image converted from SD image has a different image characteristic from a real HD image signal because of source acquisition and editing and has more severe artifacts than the real HD image signal. In more detail, this is due to a resolution decrease and low compression rate image storing of a capturing device, editing and scaling using a composite device, or up-converting. In this case, MPEG artifacts, such as blocking, more severe than real HD image exist in converted HD image, and an artifact, such as dot-crawl or cross-color, or a format conversion error exists. Thus, in any case, gradation and detail of the converted HD image decreases compared to the real HD image due to the resolution decrease. Since viewers who view image through a display device are sensitive to artifacts, the necessity to improve image quality of HD image converted from SD image by removing the artifacts is increasing. However, when artifacts are removed, a side effect such as a decrease in detail of real HD image inevitably occurs.